Effect of Microphone Configuration and Sound Source Location on Speech Recognition for Adult Cochlear Implant Users with Current-Generation Sound ProcessorsFunding Funding was provided by both NIDCD R01 DC009404 (investigator effort) and AB (participant remuneration).
Background Microphone location has been shown to influence speech recognition with a microphone placed at the entrance to the ear canal yielding higher levels of speech recognition than top-of-the-pinna placement. Although this work is currently influencing cochlear implant programming practices, prior studies were completed with previous-generation microphone and sound processor technology. Consequently, the applicability of prior studies to current clinical practice is unclear.
Purpose To investigate how microphone location (e.g., at the entrance to the ear canal, at the top of the pinna), speech-source location, and configuration (e.g., omnidirectional, directional) influence speech recognition for adult CI recipients with the latest in sound processor technology.
Research Design Single-center prospective study using a within-subjects, repeated-measures design.
Study Sample Eleven experienced adult Advanced Bionics cochlear implant recipients (five bilateral, six bimodal) using a Naída CI Q90 sound processor were recruited for this study.
Data Collection and Analysis Sentences were presented from a single loudspeaker at 65 dBA for source azimuths of 0°, 90°, or 270° with semidiffuse noise originating from the remaining loudspeakers in the R-SPACE array. Individualized signal-to-noise ratios were determined to obtain 50% correct in the unilateral cochlear implant condition with the signal at 0°. Performance was compared across the following microphone sources: T-Mic 2, integrated processor microphone (formerly behind-the-ear mic), processor microphone + T-Mic 2, and two types of beamforming: monaural, adaptive beamforming (UltraZoom) and binaural beamforming (StereoZoom). Repeated-measures analyses were completed for both speech recognition and microphone output for each microphone location and configuration as well as sound source location. A two-way analysis of variance using mic and azimuth as the independent variables and output for pink noise as the dependent variable was used to characterize the acoustic output characteristics of each microphone source.
Results No significant differences in speech recognition across omnidirectional mic location at any source azimuth or listening condition were observed. Secondary findings were (1) omnidirectional microphone configurations afforded significantly higher speech recognition for conditions in which speech was directed to ± 90° (when compared with directional microphone configurations), (2) omnidirectional microphone output was significantly greater when the signal was presented off-axis, and (3) processor microphone output was significantly greater than T-Mic 2 when the sound originated from 0°, which contributed to better aided detection at 2 and 6 kHz with the processor microphone in this group.
Conclusions Unlike previous-generation microphones, we found no statistically significant effect of microphone location on speech recognition in noise from any source azimuth. Directional microphones significantly improved speech recognition in the most difficult listening environments.
Keywordscochlear implant - beamforming - directional microphone - microphone location - R-SPACE - T-Mic - SNR - speech recognition
Received: 19 March 2019
Accepted: 25 January 2020
27 April 2020 (online)
© 2020. American Academy of Audiology. This article is published by Thieme.
Thieme Medical Publishers, Inc.
333 Seventh Avenue, 18th Floor, New York, NY 10001, USA
- 1 Gifford RH, Dorman MF, McKarns SA, Spahr AJ. Combined electric and contralateral acoustic hearing: word and sentence recognition with bimodal hearing. J Speech Lang Hear Res 2007; 50 (04) 835-843
- 2 Dorman MF, Gifford RH, Spahr AJ, McKarns SA. The benefits of combining acoustic and electric stimulation for the recognition of speech, voice and melodies. Audiol Neurotol 2008; 13 (02) 105-112
- 3 Neuman AC, Svirsky MA. Effect of hearing aid bandwidth on speech recognition performance of listeners using a cochlear implant and contralateral hearing aid (bimodal hearing). Ear Hear 2013; 34 (05) 553-561
- 4 Neuman AC, Zeman A, Neukam J, Wang B, Svirsky MA. The effect of hearing aid bandwidth and configuration of hearing loss on bimodal speech recognition in cochlear implant users. Ear Hear 2019; 40 (03) 621-635
- 5 Gifford RH, Dorman MF, Sheffield SW, Teece K, Olund AP. Availability of binaural cues for bilateral implant recipients and bimodal listeners with and without preserved hearing in the implanted ear. Audiol Neurotol 2014; 19 (01) 57-71
- 6 Dorman MF, Gifford RH. Speech understanding in complex listening environments by listeners fit with cochlear implants. J Speech Lang Hear Res 2017; 60 (10) 3019-3026
- 7 Yawn RJ, O'Connell BP, Dwyer RT. et al. Bilateral cochlear implantation versus bimodal hearing in patients with functional residual hearing: a within-subjects comparison of audiologic performance and quality of life. Otol Neurotol 2018; 39 (04) 422-427
- 8 Holder JT, Levin LM, Gifford RH. Speech recognition in noise for adults with normal hearing: age-normative performance for AzBio, BKB-SIN, and QuickSIN. Otol Neurotol 2018; 39 (10) e972-e978
- 9 Holder JT, Sheffield SW, Gifford RH. Speech understanding in children with normal hearing: sound field normative data for BabyBio, BKB-SIN, and QuickSIN. Otol Neurotol 2016; 37 (02) e50-e55
- 10 Dorman MF, Natale S, Spahr A, Castioni E. Speech understanding in noise by patients with cochlear implants using a monaural adaptive beamformer. J Speech Lang Hear Res 2017; 60 (08) 2360-2363
- 11 Spahr AJ, Dorman MF, Litvak LM. et al. Development and validation of the pediatric AzBio sentence lists. Ear Hear 2014; 35 (04) 418-422
- 12 Mosnier I, Mathias N, Flament J. et al. Benefit of the UltraZoom beamforming technology in noise in cochlear implant users. Eur Arch Otorhinolaryngol 2017; 274 (09) 3335-3342
- 13 Jansen S, Luts H, Wagener KC. et al. Comparison of three types of French speech-in-noise tests: a multi-center study. Int J Audiol 2012; 51 (03) 164-173
- 14 Holder JT, Taylor AL, Sunderhaus LW, Gifford RH. Effect of microphone location and beamforming technology on speech recognition in pediatric cochlear implant recipients. J Am Acad Audiol 2020; DOI: 10.3766/jaaa.19025.
- 15 Buechner A, Dyballa KH, Hehrmann P, Fredelake S, Lenarz T. Advanced beamformers for cochlear implant users: acute measurement of speech perception in challenging listening conditions. PLoS One 2014; 9 (04) e95542
- 16 Ernst A, Anton K, Brendel M, Battmer RD. Benefit of directional microphones for unilateral, bilateral and bimodal cochlear implant users. Cochlear Implants Int 2019; 20 (03) 147-157
- 17 Vroegop JL, Homans NC, Goedegebure A, Dingemanse JG, van Immerzeel T, van der Schroeff MP. The effect of binaural beamforming technology on speech intelligibility in bimodal cochlear implant recipients. Audiol Neurotol 2018; 23 (01) 32-38
- 18 Pearsons KS, Bennett RL, Fidell S. Speech levels in various noise environments Washington, DC: Office of Health and Ecological Effects, Office of Research and Development, US EPA; 1977
- 19 Mantokoudis G, Kompis M, Vischer M, Häusler R, Caversaccio M, Senn P. In-the-canal versus behind-the-ear microphones improve spatial discrimination on the side of the head in bilateral cochlear implant users. Otol Neurotol 2011; 32 (01) 1-6
- 20 Aronoff JM, Freed DJ, Fisher LM, Pal I, Soli SD. The effect of different cochlear implant microphones on acoustic hearing individuals' binaural benefits for speech perception in noise. Ear Hear 2011; 32 (04) 468-484
- 21 Gifford RH, Revit LJ. Speech perception for adult cochlear implant recipients in a realistic background noise: effectiveness of preprocessing strategies and external options for improving speech recognition in noise. J Am Acad Audiol 2010; 21 (07) 441-451 , quiz 487–488
- 22 Kolberg ER, Sheffield SW, Davis TJ, Sunderhaus LW, Gifford RH. Cochlear implant microphone location affects speech recognition in diffuse noise. J Am Acad Audiol 2015; 26 (01) 51-58 , quiz 109–110
- 23 Dwyer RT, Kessler D, Butera IM, Gifford RH. Contralateral routing of signal yields significant speech in noise benefit for unilateral cochlear implant recipients. J Am Acad Audiol 2019; 30 (03) 235-242
- 24 Keidser G, Dillon H, Flax M, Ching T, Brewer S. The NAL-NL2 prescription procedure. Audiology Res 2011; 1 (01) e24
- 25 Revit LJ, Killion MC, Compton-Conley CL. Developing and testing a laboratory sound system that yields accurate real-world results. Hear Rev 2007; 14 (11) 54-62
- 26 Compton-Conley CL, Neuman AC, Killion MC, Levitt H. Performance of directional microphones for hearing aids: real-world versus simulation. J Am Acad Audiol 2004; 15 (06) 440-455
- 27 Lamel L, Kassel RH, Seneff S. Speech database development: design and analysis of the acoustic-phonetic corpus. Proceedings of DARPA Speech Recognition Workshop. 1989: 100-109
- 28 Loizou PC, Dorman M, Poroy O, Spahr T. Speech recognition by normal-hearing and cochlear implant listeners as a function of intensity resolution. J Acoust Soc Am 2000; 108 (5, Pt 1): 2377-2387
- 29 Dorman MF, Loizou PC, Spahr AJ, Dana CJ. Simulations of combined acoustic/electric hearing. Proceedings of the 25th Annual International Conference of the IEEE Engineering in Medicine and Biology. 2003: 199-201
- 30 Dorman MF, Spahr AJ, Loizou PC, Dana CJ, Schmidt JS. Acoustic simulations of combined electric and acoustic hearing (EAS). Ear Hear 2005; 26 (04) 371-380
- 31 King SE, Firszt JB, Reeder RM, Holden LK, Strube M. Evaluation of TIMIT sentence list equivalency with adult cochlear implant recipients. J Am Acad Audiol 2012; 23 (05) 313-331
- 32 Festen JM, Plomp R. Speech-reception threshold in noise with one and two hearing aids. J Acoust Soc Am 1986; 79 (02) 465-471
- 33 Pumford JM, Seewald RC, Scollie SD, Jenstad LM. Speech recognition with in-the-ear and behind-the-ear dual-microphone hearing instruments. J Am Acad Audiol 2000; 11 (01) 23-35
- 34 Spahr AJ, Dorman MF, Litvak LM. et al. Development and validation of the AzBio sentence lists. Ear Hear 2012; 33 (01) 112-117